This file shows land area flooding at the tract level and county for the state of Georgia. It also pulls out tract locations of high flooding as well as their subsequent counties. It then multiplies tract social vulnerability indicator percentiles by flooding proportion to create a flooding-vulnerability, which is also interactively mapped. Finally, a comparison is drawn between flooded FEMA community lifelines and area flooded by county.

The datasets are the National 100-Year flood layer (2018), CDC SVI indicators (2018), and Re-Public’s database of flooded community lifelines (all from 2018).

These estimates show that as a result of a 100-Year flood, Georgia is 14.79% flooded by land area (which likely includes wetland areas as well). Coastal counties face the brunt of flooding (up to 60% of land area flooded), though the southeastern corner of Georgia as well as various inland tracts also have high risk.

The datasets include 1966 tracts, 1960 of which are mapped. Of those 1966, 117 have null values for flood data. We assume that in the case of missing flood data, the % tract flooded is 0, though these values are graphed as NA at this time.

Tract and County Flooding

The following plot shows tract-level land area flooding.

These following table outlines a list of tracts with flooding close to or above 50%.

LOCATION CensusTractSubmergedInFlood geometry
Census Tract 9900, Liberty County, Georgia 100.000 MULTIPOLYGON (((-81.194 31….
Census Tract 9900, McIntosh County, Georgia 100.000 MULTIPOLYGON (((-81.26668 3…
Census Tract 106.01, Dougherty County, Georgia 97.789 MULTIPOLYGON (((-84.17031 3…
Census Tract 111.08, Chatham County, Georgia 96.465 MULTIPOLYGON (((-80.97446 3…
Census Tract 9, Glynn County, Georgia 94.596 MULTIPOLYGON (((-81.49668 3…
Census Tract 115, Chatham County, Georgia 89.436 MULTIPOLYGON (((-81.24293 3…
Census Tract 1.01, Glynn County, Georgia 89.077 MULTIPOLYGON (((-81.4026 31…
Census Tract 111.03, Chatham County, Georgia 86.990 MULTIPOLYGON (((-80.93591 3…
Census Tract 111.07, Chatham County, Georgia 86.810 MULTIPOLYGON (((-81.0481 32…
Census Tract 8, Glynn County, Georgia 84.995 MULTIPOLYGON (((-81.52685 3…
Census Tract 4.03, Glynn County, Georgia 84.723 MULTIPOLYGON (((-81.4637 31…
Census Tract 111.09, Chatham County, Georgia 84.652 MULTIPOLYGON (((-81.00881 3…
Census Tract 110.04, Chatham County, Georgia 81.443 MULTIPOLYGON (((-81.09841 3…
Census Tract 101.01, Chatham County, Georgia 81.036 MULTIPOLYGON (((-81.08505 3…
Census Tract 108.07, Chatham County, Georgia 79.811 MULTIPOLYGON (((-81.28884 3…
Census Tract 108.06, Chatham County, Georgia 78.148 MULTIPOLYGON (((-81.23218 3…
Census Tract 1103, McIntosh County, Georgia 76.678 MULTIPOLYGON (((-81.27939 3…
Census Tract 3, Glynn County, Georgia 75.808 MULTIPOLYGON (((-81.42155 3…
Census Tract 2, Glynn County, Georgia 74.389 MULTIPOLYGON (((-81.4131 31…
Census Tract 111.06, Chatham County, Georgia 74.253 MULTIPOLYGON (((-81.04864 3…
Census Tract 9508, Ware County, Georgia 73.418 MULTIPOLYGON (((-82.66664 3…
Census Tract 109.01, Chatham County, Georgia 72.065 MULTIPOLYGON (((-81.21253 3…
Census Tract 110.05, Chatham County, Georgia 70.939 MULTIPOLYGON (((-81.10729 3…
Census Tract 9800, Bryan County, Georgia 68.138 MULTIPOLYGON (((-81.76334 3…
Census Tract 101.02, Chatham County, Georgia 66.918 MULTIPOLYGON (((-81.06745 3…
Census Tract 9203.01, Bryan County, Georgia 66.888 MULTIPOLYGON (((-81.40496 3…
Census Tract 5.03, Glynn County, Georgia 66.376 MULTIPOLYGON (((-81.48287 3…
Census Tract 106.05, Chatham County, Georgia 66.081 MULTIPOLYGON (((-81.09853 3…
Census Tract 101.01, Liberty County, Georgia 65.873 MULTIPOLYGON (((-81.67059 3…
Census Tract 9203.05, Bryan County, Georgia 64.588 MULTIPOLYGON (((-81.32112 3…
Census Tract 1, Chatham County, Georgia 64.440 MULTIPOLYGON (((-81.1124 32…
Census Tract 105.01, Liberty County, Georgia 64.253 MULTIPOLYGON (((-81.42268 3…
Census Tract 101, Charlton County, Georgia 64.178 MULTIPOLYGON (((-82.4156 31…
Census Tract 106.02, Camden County, Georgia 62.741 MULTIPOLYGON (((-81.53934 3…
Census Tract 102.07, Liberty County, Georgia 62.336 MULTIPOLYGON (((-81.65056 3…
Census Tract 113, Dougherty County, Georgia 61.847 MULTIPOLYGON (((-84.17697 3…
Census Tract 303.05, Effingham County, Georgia 61.253 MULTIPOLYGON (((-81.23441 3…
Census Tract 1305.03, Forsyth County, Georgia 60.914 MULTIPOLYGON (((-84.04108 3…
Census Tract 106, Liberty County, Georgia 60.731 MULTIPOLYGON (((-81.60794 3…
Census Tract 1102, McIntosh County, Georgia 60.441 MULTIPOLYGON (((-81.44781 3…
Census Tract 104, Liberty County, Georgia 60.437 MULTIPOLYGON (((-81.6144 31…
Census Tract 14.03, Dougherty County, Georgia 60.239 MULTIPOLYGON (((-84.17652 3…
Census Tract 104.02, Camden County, Georgia 59.231 MULTIPOLYGON (((-81.66717 3…
Census Tract 206, Houston County, Georgia 58.750 MULTIPOLYGON (((-83.61932 3…
Census Tract 9702, Long County, Georgia 57.850 MULTIPOLYGON (((-81.83838 3…
Census Tract 111.04, Chatham County, Georgia 57.643 MULTIPOLYGON (((-80.9921 32…
Census Tract 110.06, Chatham County, Georgia 57.088 MULTIPOLYGON (((-81.06405 3…
Census Tract 106, Richmond County, Georgia 56.938 MULTIPOLYGON (((-82.00507 3…
Census Tract 105, Camden County, Georgia 56.927 MULTIPOLYGON (((-81.57688 3…
Census Tract 139, Bibb County, Georgia 55.873 MULTIPOLYGON (((-83.67269 3…
Census Tract 42.09, Chatham County, Georgia 55.710 MULTIPOLYGON (((-81.13761 3…
Census Tract 9203.06, Bryan County, Georgia 55.257 MULTIPOLYGON (((-81.35657 3…
Census Tract 115, Muscogee County, Georgia 54.743 MULTIPOLYGON (((-84.98697 3…
Census Tract 101.02, Liberty County, Georgia 54.406 MULTIPOLYGON (((-81.8244 32…
Census Tract 9702, Clinch County, Georgia 54.357 MULTIPOLYGON (((-82.9707 30…
Census Tract 33.02, Chatham County, Georgia 54.028 MULTIPOLYGON (((-81.13544 3…
Census Tract 105.02, Liberty County, Georgia 53.066 MULTIPOLYGON (((-81.51645 3…
Census Tract 1305.05, Forsyth County, Georgia 52.638 MULTIPOLYGON (((-84.07272 3…
Census Tract 304.01, Effingham County, Georgia 52.541 MULTIPOLYGON (((-81.4186 32…
Census Tract 108.01, Chatham County, Georgia 52.521 MULTIPOLYGON (((-81.34667 3…
Census Tract 10, Glynn County, Georgia 52.173 MULTIPOLYGON (((-81.78249 3…
Census Tract 106.01, Camden County, Georgia 52.130 MULTIPOLYGON (((-81.58762 3…
Census Tract 1.02, Glynn County, Georgia 51.663 MULTIPOLYGON (((-81.42259 3…
Census Tract 108.08, Chatham County, Georgia 51.114 MULTIPOLYGON (((-81.30383 3…
Census Tract 1305.04, Forsyth County, Georgia 50.288 MULTIPOLYGON (((-84.10237 3…
Census Tract 15.02, Hall County, Georgia 49.376 MULTIPOLYGON (((-84.06225 3…
Census Tract 9701, Long County, Georgia 48.778 MULTIPOLYGON (((-81.98162 3…
Census Tract 5.01, Glynn County, Georgia 48.495 MULTIPOLYGON (((-81.4925 31…
Census Tract 15.01, Hall County, Georgia 48.436 MULTIPOLYGON (((-83.98399 3…
Census Tract 104.03, Camden County, Georgia 47.634 MULTIPOLYGON (((-81.6593 30…

This dataset includes the flooded area by county, calculated by summing tracts by county.

COUNTYFP county_flooded
051 60.168931
179 58.158581
191 57.640672
029 56.550479
127 52.415600
299 52.302681
183 51.330375
049 49.601626
065 49.177023
039 45.503681
075 32.906556
095 26.505179
025 25.601968
103 23.813306
173 23.772350
181 22.844594
253 21.967847
229 20.822343
001 19.901261
021 19.799043
235 18.293711
267 17.838891
037 17.755408
271 17.483767
007 17.269310
031 17.150642
251 17.033070
129 16.857576
027 16.195223
205 16.066551
165 16.045831
245 15.786716
071 15.611222
101 14.979588
319 14.802538
209 14.531650
309 14.348986
305 14.152479
099 13.809162
047 13.546721
279 13.410809
117 13.329940
193 13.317430
061 13.270571
153 13.178795
285 12.965847
113 12.656078
147 12.510027
109 12.502574
315 12.478689
297 12.471795
087 12.380623
139 12.140891
275 12.140745
115 11.948528
069 11.761688
081 11.686528
211 11.677079
003 11.660754
239 11.651995
289 11.643400
019 11.298666
215 11.070629
175 11.065599
177 11.007648
105 10.966073
201 10.861332
009 10.808063
151 10.806753
257 10.719266
013 10.490497
277 10.355827
161 10.194614
313 10.099054
155 10.022441
217 9.845303
185 9.831183
035 9.792955
255 9.770228
015 9.602915
131 9.584028
149 9.446411
067 9.380054
043 9.354382
077 9.212994
213 9.188935
097 9.068126
091 8.799428
259 8.796006
033 8.562536
063 8.526302
163 8.501753
133 8.485584
145 8.380333
321 8.334257
157 8.306350
273 8.194701
199 8.154257
107 8.110432
005 8.079400
057 7.885661
053 7.795325
073 7.790258
045 7.734566
121 7.726881
089 7.719809
303 7.703149
059 7.685061
237 7.674094
283 7.609106
247 7.521752
269 7.346512
287 7.330606
189 7.227328
135 7.175024
291 7.160038
167 7.131982
079 7.099950
307 7.077943
093 7.047966
265 7.022541
055 6.953729
261 6.852495
125 6.666187
233 6.642979
221 6.641154
017 6.615973
219 6.575371
293 6.513151
227 6.271363
263 6.246222
111 6.157145
011 6.047913
083 5.940659
231 5.736202
143 5.411986
023 5.353882
171 5.317345
195 5.268399
123 5.249603
317 5.228024
085 5.152320
281 5.085194
225 4.881617
169 4.807240
241 4.793756
223 4.694916
243 4.096941
295 4.019698
141 3.720443
249 3.653027
207 3.596875
301 3.521671
137 3.439232
311 2.976795
187 2.761211
159 2.630136
197 2.271280
119 2.191250

The interactive plot below includes county names and subsequent flooding.

Looking specifically at our 7 counties of analysis: Chatham: 60.169% flooded Liberty: 58.159% flooded McIntosh: 57.641% flooded Stewart: 8.796% flooded Colquitt: 15.611% flooded Rabun: 4.794% flooded Whitfield: 10.099% flooded

Social Vulnerability Indicators and Flooding

For every tract, we calculated a combined social vulnerability-flooding score by multiplying the vulnerability percentile (ranked at the state level) with the tract flooding. This was done for the overall vulnerability percentile, socioeconomic vulnerability percentile, household composition vulnerability percentile, language isolation vulnerability percentile, and housing structure vulnerability percentile.

Below is a table that includes the top 10 most “vulnerable” tracts based on overall flooding and SVI rankings.

LOCATION tract_vuln CensusTractSubmergedInFlood RPL_THEMES geometry
Census Tract 106.01, Dougherty County, Georgia 0.9623415 97.789 0.9841 MULTIPOLYGON (((-84.17031 3…
Census Tract 8, Glynn County, Georgia 0.8155270 84.995 0.9595 MULTIPOLYGON (((-81.52685 3…
Census Tract 9, Glynn County, Georgia 0.7985794 94.596 0.8442 MULTIPOLYGON (((-81.49668 3…
Census Tract 109.01, Chatham County, Georgia 0.7114257 72.065 0.9872 MULTIPOLYGON (((-81.21253 3…
Census Tract 1, Chatham County, Georgia 0.6315120 64.440 0.9800 MULTIPOLYGON (((-81.1124 32…
Census Tract 1103, McIntosh County, Georgia 0.6123505 76.678 0.7986 MULTIPOLYGON (((-81.27939 3…
Census Tract 9508, Ware County, Georgia 0.5971820 73.418 0.8134 MULTIPOLYGON (((-82.66664 3…
Census Tract 101, Charlton County, Georgia 0.5970479 64.178 0.9303 MULTIPOLYGON (((-82.4156 31…
Census Tract 113, Dougherty County, Georgia 0.5838975 61.847 0.9441 MULTIPOLYGON (((-84.17697 3…
Census Tract 101.01, Chatham County, Georgia 0.5649020 81.036 0.6971 MULTIPOLYGON (((-81.08505 3…

This graphic shows the scores from the overall vulnerability percentile.

This graphic shows the scores from the socioeconomic vulnerability percentile.

This graphic shows the scores from the household composition vulnerability percentile.

This graphic shows the scores from the language isolation vulnerability percentile.

This graphic shows the scores from the housing structure vulnerability percentile.

Land Area Flooding and Lifeline Flooding

Using Re-Public community lifeline flooding data at the county level, we wanted to assess the relationships between land area flooded and lifeline flooding. Outliers in particular may give an indication of which counties have more pressing mitigation needs related to critical infrastructure, and a relationship between both would encourage more robust flood area analysis and hazard mitigation planning.

There is little correlation between the two parameters (R^2 = 0.08611). While there are 119 points not labeled, those points come in the center. We are especially interested in the outliers, especially ones experiencing high land area flooding or high lifeline flooding. While some of the coastal counties face very flood risk by land area, inland counties with high social vulnerability (ex. Colquitt) may deal with a large loss of critical infrastructure.

## 
## Call:
## lm(formula = county_flooded ~ lifelines_impacted_ratio, data = GA_county_flooding_lifelines)
## 
## Residuals:
##     Min      1Q  Median      3Q     Max 
## -19.105  -5.729  -2.366   0.577  43.448 
## 
## Coefficients:
##                          Estimate Std. Error t value Pr(>|t|)    
## (Intercept)                 3.956      2.520   1.570 0.118417    
## lifelines_impacted_ratio   43.354     11.272   3.846 0.000174 ***
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 11.22 on 157 degrees of freedom
## Multiple R-squared:  0.08611,    Adjusted R-squared:  0.08029 
## F-statistic: 14.79 on 1 and 157 DF,  p-value: 0.000174